Sound absorptive multilayer composite

• US 7,320,739 B2
• Filed: 07/01/2004
• Issued: 01/22/2008
• Est. Priority Date: 01/02/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Liu, Xiaohe, Thompson, Delton R. Jr.
• Primary Examiner(s): GOFF II, JOHN L
• Application Number:
  US10/884,545
• Publication Number:
  US 20040231915A1
• Time in Patent Office: 1,300 Days
• Field of Search: 156/308.2, 156/309.6, 156/324, 156/196, 181/286, 181/290, 181/291, 181/292
• US Class Current: 156/308.2
• CPC Class Codes: B01D 2325/26 Electrical properties
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: B01D 67/009 with wave-energy, particle-radiation or plasma
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B32B 2255/02 on fibrous or filamentary layer
• CPC Class Codes: B32B 2262/0276 Polyester fibres
• CPC Class Codes: B32B 2262/101 Glass fibres
• CPC Class Codes: B32B 2262/12 Conjugate fibres, e.g. core/sheath or side-by-side
• CPC Class Codes: B32B 2262/14 Mixture of at least two fibres made of different materials
• CPC Class Codes: B32B 2266/025 Polyolefin
• CPC Class Codes: B32B 2266/0278 Polyurethane
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2307/102 Insulating
• CPC Class Codes: B32B 2307/724 Permeability to gases, adsorption
• CPC Class Codes: B32B 2307/7242 Non-permeable
• CPC Class Codes: B32B 2605/08 Cars
• CPC Class Codes: B32B 27/065 of foam
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 5/02 : characterised by structural features of a fibrous or filamentary layer layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02
• CPC Class Codes: B32B 5/04 : characterised by a layer being specifically extensible by reason of its structure or arrangement , e.g. by reason of the chemical nature of the fibres or filaments
• CPC Class Codes: B32B 5/18 : characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/24 : one layer being a fibrous or filamentary layer
• CPC Class Codes: B32B 5/245 : another layer next to it being a foam layer
• CPC Class Codes: B32B 5/32 : at least two layers being foamed and next to each other
• CPC Class Codes: B32B 7/022 : Mechanical properties
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B60R 13/011 : for internal load compartments, e.g. car trunks
• CPC Class Codes: B60R 13/02 : Internal Trim mouldings ; Internal Ledges; Wall liners for passenger compartments; Roof liners B60R13/01 takes precedence ; padded linings for the vehicle interior B60R21/04; arrangements or adaptations of floor mats or carpets in vehicles B60N3/04; internal lining for trains B61D17/18
• CPC Class Codes: B60R 13/0256 : Dashboard liners
• CPC Class Codes: B60R 13/0815 : Acoustic or thermal insulation of passenger compartments wall or roof liners integrating the insulating function B60R13/02; insulating floor mats or carpets B60N3/04
• CPC Class Codes: B60R 13/083 : for fire walls or floors
• CPC Class Codes: B60R 13/0838 : for engine compartments
• CPC Class Codes: G10K 11/162 : Selection of materials
• CPC Class Codes: G10K 11/168 : Plural layers of different materials, e.g. sandwiches
• CPC Class Codes: Y10T 156/1002 : with permanent bending or reshaping or surface deformation of self sustaining lamina

Abstract

A sound absorptive multilayer composite having an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅓ the final composite thickness, an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness at least about 1/10 the final composite thickness and a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls can provide improved acoustic performance. For example, existing vehicular headliner designs may be improved by adding a properly chosen and properly positioned semipermeable airflow-resistive membrane, a properly chosen and properly positioned air-impermeable barrier, or a properly chosen and properly positioned open cell foam layer.

Claims

1. A method for making a multilayer sound absorptive composite comprising:

a) providing a stack of layers comprising in order an air-impermeable barrier, an air-permeable reinforcing core comprising a foam and having an airflow resistance of at least about 100 miks Rayls and a thickness at least about ⅓

the final composite thickness, an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 miks Rayls and a thickness at least about 1/10 the final composite thickness, and a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 miks Rayls, and

b) laminating the stack of layers together under sufficient heat and pressure to form a unitary sound absorptive multilayer composite.

2. A method according to claim 1 wherein the composite has a cavity depth at least 90% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

3. A method according to claim 1 wherein the composite has a cavity depth at least 95% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

4. A method according to claim 1 wherein the membrane has an airflow resistance of about 500 to about 1500 miks Rayls.

5. A method according to claim 1 wherein the membrane is an outermost layer of the composite.

6. A method according to claim 1 wherein the membrane is colored or textured to provide a decorative appearance.

7. A method according to claim 1 wherein the membrane comprises a nonwoven web.

8. A method according to claim 1 wherein the membrane comprises knit or woven fabric comprising microdenier yarns.

9. A method according to claim 1 wherein the membrane comprises multicomponent fibers.

10. A method according to claim 1 wherein the membrane comprises split or splittable bicomponent fibers.

11. A method according to claim 1 wherein the foam or fibrous pad has a thickness at least about ¼

the total composite thickness.

12. A method according to claim 1 wherein the foam or fibrous pad has a thickness at least about ½

the total composite thickness.

13. A method according to claim 1 wherein the foam or fibrous pad has an airflow resistance less than about 500 miks Rayls.

14. A method according to claim 1 wherein the core has a thickness less than about ⅔

the total composite thickness.

15. A method according to claim 1 wherein the core has a thickness less than about ½

the total composite thickness.

16. A method according to claim 1 wherein the core has an airflow resistance less than about 2000 miks Rayls.

17. A method according to claim 1 wherein the stack further comprises an outermost nonrestrictive air-permeable decorative layer adjacent the membrane.